The Clapper (or similar device) for wall switch?

Similar , better, expandable but not with the clap disease is X10 sold as plug in power at radioshack .

There's also a sensor which turns on the circuit whenever it detects movement in the room, which can be used to automatically turn on lights (such as in a closet, or in a conference room). It's available at the big box stores and electrical supply stores.

I installed one in the kitchen, but found that if someone stood still too long the lights would go off -- very disconcerting -- so later removed it. Regards --

Check out Smart Home

------- Wow, more expensive than I thought.

I thought it reasonably priced. One light switch and controller will cost about $48. Additional modules are $10 to $15. Mine is over 20 years old, so we're looking at $2 a year for convenience, security, economy of operation. I have a manual controller on the nightstand. If I hear noise outside at night, I hit a button and lights go on outside. What is that safety worth to you?

I'm not ready to spend $80 on a voice activated dimmer, but for normal light controller security, this is a pretty cheap way to go.